New materials and creative strategies are needed to combat the deterioration of elastomeric components in 20th century collections. Unstable and actively degrading polymers are commonly observed in aging mass-produced objects: in a growing number of case studies these are elastomers. With the expectation that advances in polymer technology now provide more stable options with similar properties, various samples (polysiloxanes, polychloroprenes, hot-melt adhesives and other proprietary products) are being tested by the Brooklyn Museum Conservation lab for archival and working properties to determine their suitability for reinforcing or replacing elastomeric components in works of art, design and historical collections.
Elastomer is a broad term for any natural or synthetic polymer that has elastic properties and is often used interchangeably with the word rubber. Rubbers were used for many applications throughout the 20th century and generally chosen for their flexible and shock absorbent nature. Many small appliances, for instance, were fitted with elastomeric feet to keep them in place on desks and countertops and to absorb vibrations. Toys, costumes, models, furniture, and other design objects in collections have molded, bendable parts - wheels, gaskets, shock mounts, shoe soles, cords, etc. – that are made from a group of elastomeric materials that is growing larger each day. Deteriorating load-bearing elements, like feet, pads, and mounts, present very pressing concerns, since these objects cannot even support themselves in storage.
Vulcanized rubber was patented in the 1840s in both Britain and the US. By the early part of the 20th century investigations into developing synthetic rubber were well underway. These efforts were advanced and delayed by both World Wars but by the 1950s numerous synthetic rubbers (including butadiene, polychlorine, polysiloxane, and polysufide rubbers) were being produced at factories throughout Europe and the US. Synthetic rubber surpassed natural rubber production worldwide in the early 1960s. The last decades of the 20th century saw the invention of thousands of new elastomers and the rapid development of thermoplastic elastomer market. Current fields of growth include renewable/ sustainable (biofeedstock) elastomers, and self-healing elastomers.
Recently the Brooklyn Museum was faced with the active deterioration of the wheels on a Nari Ward sculpture. The piece Crusader (2005) includes a used shopping cart as a main component of the work, which was originally used in a performance and has since been loaned to multiple venues - the piece is currently on view at the New Museum in Nari Ward: We the People. As the polyurethane wheel treads degrade, they lose their capacity to function, thus sacrificing elements of the work’s context and history.
Another example from the Brooklyn Museum’s collection is a table designed by Ali Tayar, Michael’s Table (1991) that has damaged rubber pads buffering the glass tabletop from the metal and wood frame. Without these integral pieces the glass top rubs against the metal and is not held in place meaning that displaying this piece, even for a short time, will require some Conservation intervention.
For these examples among others, we are researching and testing possible replacement materials and alternate solutions for the treatment and restoration of objects with deteriorating elastomeric components. Such research highlights the importance of questioning the implications of altering these components, the benefits of case-by-case decision making versus standardized policies and the acceptability of replacing elastomers that perform a structural function.
Posted by Kate Wight Tyler
